Kelly Osbourne gave up alcohol for fiance Luke Worrall.
The presenter - who got engaged to the model in March 2009 - stopped drinking altogether once she met Luke and believes he has made her a "better person".
She said: "He's turned me into a better person. He really has. I didn't care before I met Luke. I was out every night, drunk. I didn't have somebody to be a better person for and then that all changed when I met Luke."
The 25-year-old star is now completely teetotal because she doesn't trust how she might behave after she's had a few drinks.
She explained to more! magazine: "I don't drink at all. Even a glass of wine at dinner would probably mean me going home, getting s**t-faced and then being on drugs and doing something stupid that I have to spend the next three months apologising for.
"I don't like drinking that much as I hate throwing up and the taste of alcohol. I'd look at somebody who has a half-empty glass in front of them and think, 'How can they leave that?' whereas mine, it's like 'Glug' and it's gone. 'Can I have another one? I'll be alright.' "
Kelly is so focused on staying sober she does her best to stop herself from being around alcohol as she doesn't want to be tempted.
She explained: "In the culture in England it's hard to explain to people you don't want to drink, as they look at you like you're f***ing crazy. There have been times the hotel I'm staying in has sent up three bottles of champagne and I send them back. What am I going to do with it staring at me in a bucket? I don't want it."
Kelly has been in rehab three times, most recently to seek help for a dependency on prescription drugs.